The Nashoba Brook Stone Chamber is an underground stone structure in the woods of the Nashoba Brook Conservation Area of Acton, Massachusetts. Its more common name is the "potato cave", which comes from the traditional assumption that it was once used as a root cellar. Research and excavation from 2006 supports this assertion, finding evidence of construction from the 18th or 19th century for the purpose of storing food. Some argue that it may originally have been a pre-colonial native American ceremonial stone landscape structure.